The present invention relates to displays, and more particularly to an improved mount for securing a liquid crystal display frame to a chassis.
Liquid crystal displays (LCDs) operate by reducing the transmissibility of light through a thin layer of liquid crystalline material (hereinafter referred to as the "liquid crystal") when an electric field is applied. Since the reduced transmissibility effect is localized, shapes and characters can be drawn on an LCD by carefully controlling the application of the electric field. The liquid crystal of an LCD is sensitive to external forces and stresses which can degrade its visual output. Deflection of the liquid crystal caused by the application of external forces may result in a phenomenon known as "Newton rings". Newton rings may be multi-colored or rainbow type distortion visible on the LCD when such a deflection of the liquid crystal occurs. The existence of Newton rings is undesirable, and in many cases unacceptable.
Typically, the liquid crystal of an LCD is secured to an LCD frame. The LCD frame supports the liquid crystal and other components such as light filters and protective windows. The LCD frame is adapted to be received into and supported by a chassis. To satisfy manufacturing tolerance requirements and to facilitate ease of assembly, a designed gap or clearance exists between the chassis and the frame when the frame is inserted into the chassis. In most applications, such as use of the LCD in an aircraft cockpit, existence of this gap allows unacceptable movement and shifting of the liquid crystal and frame. Therefore, the LCD frame must be secured to the chassis.
Typically, the LCD frame is rigidly secured to the chassis with mounting hardware, such as screws or nuts and bolts, positioned around the LCD at various locations. As the hardware is tightened, the LCD frame deflects outward toward the chassis to eliminate the gap between the two components. As the LCD frame deflects outward, the stresses are transferred to the liquid crystal and Newton rings result.
Consequently, a need exists for an improved LCD in which the frame can be secured to the chassis without causing Newton rings to develop.